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N. PETERa Pmwuxhngnpher, wnshingmn, D. C.

` UNITED ST.etres` PATENT OFFICE.

Y RAOUL PIERRE PIo'rEr, or GENEvA,sw1TzEnLnND.

CONSTRUCTION "OF irSHI PS.

SPECIFICATION forming `part of Letters Patent No. 251,793, dated J'anuary, 1882.

l Application filed October 12,` 1881. 1 (No model.) Patented in France June 2, 1881. Y

To all whom it may concern:

Be it known that I, RAOUL PIERRE PIc'rIII,` a citizen of Switzerland, residing at Geneva, in

the Republic of Switzerland, have invented new and useful Improvements in the (Jonstr'uction given tothe hull or body is based upon the- Archimedean principle, which is a principle of statical mechanics. Such vessels all displace a volume of water the Weight of which is equal to the Weight of the vessel, and the volume or mass submerged is but slightly affected by the speed at which the vessel may be propelled.

To obtain great speed the constructor has sought to give to the hull or body of the vessel that form which will most readily displace its own volume of water, and this has resulted in the adoption of line lines in their construction. Vessels designed to be propelled at a great speed, as now constructed, have a sharp bow Vand stern, the greatest sectional area being amidship. Under such circumstances the power employed for their propulsion increases in proy portion to the speed.

The object of this invention is to facilitate the navigation of vessels and increase their speed without materially or relatively increasingthepropellingpower; anditconsists,essen tially, in combining with the principle of Ar` chimedes the principle of hydrodynamics by giving the hull or body of the'vessel such a form as will tend to raise the same out of the water. The result of the combination of these two principles will be a diminution of the power applied to propel the vessel in proportion to the increase of its speedinstead of an increase in the power applied iu proportion to the increase of the speed.

Inthe accompanying drawings, Figure I is a vertical longitudinal section,Fig. II a plan view, and Fig. III an end elevation, of a vessel constructed according to my invention.

In carrying out the above-described combined principles I give tothe keel of the vessel the parabolic curve A B, Fig. I, the concavity thereof, as shown,trendin g downward and rearward. This keel or bottom is represented by a flat or horizontal surface, R S, Fig. II, extending longitudinally of the vessel, and that in longitudinal section forms the parabolic curve 'Figs-Land II, impart to thelbottomvortkeel of `2th evessel, to-whichithey aresecurely attached, t-helnecessarypowerofi resistance. These ribs or knees correspond inform to the bottom and Ssides of the vessel-thatisto say,` they all have arectilinear portion corresponding with R S and a curved portion, U V U K D L, which latterimparts to the sides ofthe vessel the required power of resistance.

It will be seen that a vessel constructed upon the principles abovedescribedwill be composed of two essentially and geometrically different parts, namely: one part that is flat transversely and extends in a parabolic curve longitudinally of the vessel, and a .second part formed by rounded or curvedl lines connecting the former with the planking. A vessel so constructed will float, when at rest, according to the Archimedean principle, the float-line being at M M', for iustance,Figs. I and III. y

Supposin g a propeller to be exerting its power at the stern- B of the vessel, moving the same at a given speed in the direction` of the curve B A, two concomitant ei'ects will be produced thereby: First, the stationary Water upon which the vessel moves will be caused to move also,`

and in a direction from the surface downward, this being due to the parabolic curve of the bottom of the vessel; second, the reaction of this mechanical action of the downward movement ofthe water upon' the weight or blodyof the vessel will be exerted in an opposite direction, and the vessel will consequently displace a proportionally smaller volume of water. If the speed is increased, this downward move ment of the water increases also, and will tend to gradually lift the boat out of the water and cause ittoglide upon its surface. Under these conditions it is evident that the submerged AB. A series ofribs or knees, A EF H B,

midship or greatest transverse sectional area of the vessel will become a factor of speed. Hence the greatest total resistance opposed to the movement of the boat is itself a factor of speed.

When constructed as described a vessel will rise-"out ot' the water progressively, and that at aspeed varying from zero tothe greatest speed the power applied can produce, the water line being constantly and gradually displaced from the line M M to the'limit M M, Figs. I and III.

I am aware that it has been proposed to build vessels the keels of which are constructed IOO ance of which is exerted at or near the stern of the vessel. In the former case the resistance is a practically uniform one along the whole length ot the inclined-surface, While in the latter case it is agradually-increasiug one.

It has also been proposed to et'ect the results herein claimed by providing the keel or bottom of a vessel with an outwardly-open chamber or recess, into which air is forced for the purpose ot' raising the vessel out ofthe Water,and in this case the results are the same asin the case of a vessel having an inclined straight bottom.

Having now described my invention, what I claim is- 2. A vessel havin g its greatest diameter amidl ships and a bottom of practically equal diameter throughout its length, constructed to form a parabolic curve trending downward from stem to stern, and having its greatest concavity at or near the stern7 substantiallyas and for the purpose specified.

In witness that I claim the foregoing I have hereunto set my hand this 17th day of September, 1881.

RAOUL PIERRE PIOTET.

Witnesses:

BRosE WATTEVILL, LYELL T. ADAMS. 

